Railcar bodyshells manufactured by using stainless steel have been conventionally known. The bodyshells manufactured by using stainless steel have many advantages. For example, since the bodyshells manufactured by using stainless steel do not corrode, paint is unnecessary, and maintenance is easy. FIG. 13(a) is a front view of a side bodyshell of a conventional railcar when viewed from a car interior side, and FIG. 13(b) is a cross-sectional view taken along line XIIIb-XIIIb of FIG. 13(a). As shown in FIGS. 13(a) and 13(b), a side bodyshell 101 includes: a side outside plate 102; vertical frame members 103 located at a door pocket portion and welded to an inner surface of the side outside plate 102; and horizontal frame members 104 located under a window opening and welded to the inner surface of the side outside plate 102. Each of PTLs 1 and 2 proposes a railcar bodyshell in which the frame members are laser welded to the outside plate. In accordance with this, weld marks on an outer finished surface of the outside plate become less visible, so that the appearance of the railcar bodyshell can be improved.
FIG. 14 is a perspective view showing a bodyshell configured such that respective members of a conventional railcar are laser welded to one another. FIG. 15 is a front view of the side bodyshell of FIG. 14 when viewed from the car interior side. FIG. 16(a) is a major portion enlarged view showing the vicinity of the window opening of the side bodyshell of FIG. 15. FIG. 16(b) is a cross-sectional view taken along line XVIb-XVIb of FIG. 16(a). As shown in FIG. 14, a bodyshell 111 includes: a roof bodyshell 112, side bodyshells 113, end bodyshells (not shown), and an underframe 114. As shown in FIGS. 15 and 16, the side bodyshell 113 is formed such that: horizontal frame members 118 are laser welded to a side outside plate 117 from the car interior side, the side outside plate 117 having a window opening 117a; and vertical frame members 119 are laser welded to the horizontal frame members 118 from the car interior side.
Since high stress is generated at corner portions of a peripheral portion defining the window opening 117a, reinforcing plates 115 are respectively provided at the corner portions. Each of the reinforcing plates 115 has a substantially L shape corresponding to the corner portion and is spot welded to the side outside plate 117. Here, the reason why the reinforcing plate 115 is spot welded is because due to structural restrictions of a laser welder, the reinforcing plate 115 cannot be laser welded to a reinforced portion. For example, in an example shown in FIG. 16, the reinforcing plate 115 is spot welded to the side outside plate 117 by ten spots.
Citation List
Patent Literature
PTL 1: Japanese Laid-Open Patent Application Publication No. 2007-112344
PTL 2: Japanese Laid-Open Patent Application Publication No. 2007-137263
PTL 3: Japanese Laid-Open Patent Application Publication No. 5-213189
PTL 4: Japanese Laid-Open Patent Application Publication No. 6-263029
PTL 5: Japanese Laid-Open Patent Application Publication No. 7-81556
PTL 6: Japanese Patent No. 3219278